为何html中嵌入mp4格式视频播放不了

<object width="300" height="300" type="video/x-ms-asf" url="http://localhost/younao01.mp4" data="younao01.mp4" classid="CLSID:6BF52A52-394A-11d3-B153-00C04F79FAA6">
<param name="url" value="younao01.mp4">
<param name="filename" value="younao01.mp4">
<param name="autostart" value="1">
<param name="uiMode" value="full" />
<param name="autosize" value="1">
<param name="playcount" value="1">
<embed type="application/x-mplayer2" src="http://localhost/younao01.mp4" width="100%" height="100%" autostart="true" showcontrols="true" pluginspage="http://www.microsoft.com/Windows/MediaPlayer/"></embed>
</object>